Apparatus for producing multiple sheet glazing units



Aug. 14, 1962 c. H. COWLEY 3,043,944

APPARATUS FOR PRODUCING MULTIPLE SHEET GLAZING UNITS Original Filed Oct.24, 1957 4 Sheets-$heet 1 IN V EN TOR.

A TTORNE Y5 Aug. 14, 1962 c. H. COWLEY 3,043,944

APPARATUS FOR PRODUCING MULTIPLE SHEET GLAZING UNITS 4 Sheets-Sheet 2Original Filed Oct. 24. 1957 IZO IN V EN TOR. @zwww. 14 (3x067 BY zldflegtwyx A TTORN E YS Fig.

Aug. 14, 1962 c. H. COWLEY 3,048,944

APPARATUS FOR PRODUCING MULTIPLE SHEET GLAZING UNITS Original Filed Oct.24. 195'? 4 Sheets-Sheet 3 IN V EN TOR.

ZMe Jae/0pc A TTORNE YS Aug. 14., 1962 c. H. COWLEY 3,048,944

APPARATUS FOR PRODUCING MULTIPLE SHEET GLAZING UNITS Original Filed Oct.24, 1957 4 SheetsSheet 4 V V I g g i 23 g 2 66 I n r I g INVENTOR. g QGMCM A! 601062 F .11 f lmegg it Stat atet 3,il48,944 Patented Aug. 14,1962 thee ration of Ohio Original application Oct. 24, 1957, Ser. No.692,181, now Patent No. 2,995,869, dated Aug. 15, 1961. Divided and thisapplication Feb. 12, 1960, Ser. No. 13,976

11 Claims. (Cl. 491) This invention relates broadly to all-glassmultiple sheet glazing units and more particularly to an apparatus forproviding an improved dehydration or breather hole in such multiplesheet glazing units.

This application is a division of application Serial No. 692,181, filedOctober 24, 1957, now Patent No. 2,995,- 869.

Multiple sheet glazing units generally comprise two or more sheets ofglass which are sealed entirely around their edge portions in spacedrelation to provide a hermetically sealed dead air space therebetween.Due principally to their insulating and condensation preventingqualities, such units are valuable in the building trades as windows 1fcl): buildings, show cases, vehicles, refrigerators, and the In order toprovide a multiple sheet glazing unit with both heat insulating andcondensation preventing qualities, it is necessary that humid or evenair of normal moisture content be removed from the space between thesheets of glass making up the unit. This may be done by partialevacuation or by replacing the moisture containing air with dry air orgas which is best suited to the conditions to which the unit is to beexposed. To make possible the removal of air from the enclosed spacebetween the glass sheets, with or without substituting dry air or gastherefor after the sheets have been joined at the marginal edges toenclose the space, a means of access to the space must be provided inthe sealed unit. Likewise, after the space has been properly dehydratedthe means of access must be permanently sealed to hermetically close theunit.

The conventional way of providing access to the enclosed space betweenthe sheets of glazing units of this character, has been to drill orotherwise cut an opening through one of the sheets before they aresealed together. In this Way the internal and external pressures mayalso be equalized While the edge portions of the sheets are being fusedtogether. However, drilled holes of this type have several disadvantagesin that the glass oftentimes breaks when drilled, or small fissures areproduced around the hole in drilling which cause the sheet to break whenexposed to thermal shock. Additionally, when the holes are drilledthrough the face surfaces of the glass sheets, the sealing material is,in many cases, exposed after the unit has been glazed leaving itvulnerable to sharp instruments such as a glaziers putty knife, etc.

It is a primary object of this invention to provide an all-glassmultiple sheet glazing unit in which a dehydration hole or breather holeis provided along the sealed edge wall of the unit.

Another object of the invention is to provide an apparatus for formingdehydration holes or breather holes in the sealed edge portions ofall-glass multiple sheet glazing units during the sealing of the sheetstogether.

A further object of the invention is to provide an apparatus for formingdehydration or breather holes in the sealed edge portions of all-glassmultiple sheet glazing units while the sheets and the heat source forfusing them together are moving relative to one another.

Another object of the invention is to provide an apparatus for formingdehydration or breather holes in the sealed edge portions of all-glassmultiple sheet glazing units by placing a hollow insert in the sealededge portions while said portions are being fused.

Still another object of the invention is to provide an apparatusinserting a hollow metallic insert in the sealed edge portions of anall-glass multiple sheet glazing unit to provide an access hole to theenclosed space, the exposed end of the insert being substantially flushwith the outer surface of the edge portions.

Another object of the invention is to provide a relatively simpleinexpensive apparatus for forming such dehydration or breather holes inall-glass multiple sheet glazing units.

Other objects and advantages of the invention will become more apparentduring the course of the following description when taken in connectionwith the accompanying drawings.

In the drawings, wherein like numerals: are employed to designate likeparts throughout the same:

FIG. 1 is a perspective view of an all-glass multiple sheet glazing unitprovided with a dehydration hole according to the invention;

FIG. 2 is a plan view of the apparatus for producing glazing unitsshowing a conveyor apparatus in relation to fusing burners and holeforming means;

FIG. 3 is a fragmentary sectional view of the apparatus for producingall-glass glazing units taken along 3-3 of FIG. 2;

FIG. 4 is afragmentary plan view of a forming tool and a hole formingmeans according to the invention;

FIG. 5 is a fragmentary sectional view taken along 55 of FIG. 4;

FIG. 6 is a sectional view taken along 6-6 of FIG. 4;

FIG. 7 is a sectional end elevational view taken along 77 of FIG. 4;

FIG. 8 is a sectional elevation view taken along 88 of FIG. 4;

FIG. 9 is a fragmentary plan view of a device for holding a noveldehydration hole insert in accordance with the invention;

FIG. 10 is a side elevational view partially in section taken along 10-10 of FIG. 9;

FIG. 11 is a sectional end view of the marginal edges of two sheets ofglass;

FIG. 12 is a sectional end view of a sealed edge wall of an all-glassglazing unit;

FIG. :13 is a sectional view of an all-glass glazing unit showing adehydration hole made in accordance with the invention;

FIG. 14 is an electrical control circuit for use in the invention; and

FIG. 15 is a sectional view of a modified form of insert being placed inthe edge wall of a glazing unit according to the invention.

Referring now to the drawings, there is shown in FIG. 1 an all-glassglazing unit 20 produced in accordance with the present invention whichcomprises two or more sheets of glass 21 and 22 maintained spaced fromone another by a fused edge wall 23 enclosing a space 24 therebetween.The dehydration or breather holes with which this invention isconcerned, are provided in at least one of the edge wall portions 23 asshown at 25.

Briefly, the invention contemplates inserting a hollow sleeve betweenthe spaced marginal edge portions of a pair of glass sheets and fusingthese edge portions together around the sleeve to provide .a dehydrationor breather hole in the sealed edge wall. 7

As can be seen best in FIGS. 2 and 3 a preferred apparatus for producingthe improved all-glass multiple sheet glazing unit of this invention isdesignated generally by the number 26 and includes a tunnel type furnace27, means 28 for supporting spaced glass sheets within the furnace, anda conveyor 29 mounted outside 3 the furnace for moving the sheetsupporting means through the furnace.

Turning now specifically to the furnace 27 (FIGS. 2 and 3) it isconstructed of a lower wall 36, two side walls 31 and 32, and anoverhead or ceiling wall 33 all made of firebrick or other suitablenoninfiammable material. The lower wall 30 is supported bylongitudinally extending beams 34 which are supported by verticalmembers 35. For the purpose of illustration only heat is shown suppliedto the furnace 27 by Nichrome or other wire filaments 36 fastened to theside walls 31 and 32. However, any one of a number of well known heatingtechniques may be used to produce the desired heating effect. Also inorder to permit the moving of the sheet support means 28 within thefurnace by the conveyor 29 outside the furnace, there is provided in theside wall 32 a slot extending longitudinally with respect to thefurnace. Within the furnace there are a plurality of sealing areas, oneof which is designated by the letter A through which the sheets 21 and22 pass during the sealing process.

In being moved through the sealing areas, such as A, the sheetsupporting means 28 and the sheets 21 and 22 are supported and carriedby the conveyor 29 which includes generally a rail support frame 38 anda carriage 39 adapted to ride on rails 40 carried by the rail supportframe.

Carriage 39 which is adapted to carry the sheets 21 and 22 through thefurnace 27, includes a substantially rectangular base section providedwith a plurality of grooved wheels 41 shaped to substantially thecurvature of the rails 40 so as to guide the carriage as it moves thesheets through the furnace. Axles 42 for receiving wheels 41 arejournaled in bearings (not shown) on the underside of the carriage base.

The glass sheet supporting means 28 comprises a pair of vacuum platens43 and 44 to support the glass sheets 21 and 22 in a substantiallyvertical and spaced position with respect to one another as the sheetsare moved through the furnace and the sealing section A. In particular,the vacuum platen 43 is maintained on one end of a stub shaft 45 whichis rotatably mounted adjacent, and the other end is journaled in abearing 46 on cross arm 47. Cross arm 47 is supported by means of pillowblocks 48 which are secured to conveyor 29 by means of shafts 49 securedthereto. Vacuum platen 44 is mounted on one end of a relatively longshaft 50 and is spaced from platen 43 a distance equal to the width ofan all-glass multiple sheet glazing unit to be produced. The shaft 50 isrotatably journaled in a suitable bearing (not shown) and is turned by ahandle (not shown) after each pair of edges of the sheets has been fusedtogether in order to present an unsealed pair of edges in sealingposition.

As illustrated in FIG. 3, each of the platens 43 and 44 is provided withvacuum cups 51 by means of which a partial vacuum can be applied to theglass sheets in order to hold them against the faces of the respectiveplatens. Grooves 52 are provided along each of the faces of the platensin order to connect vacuum cups 51 to a central opening (not shown)provided in the stub shaft 45 and the longer shaft 50 with a pipe member53 connected to a suitable vacuum pump 54.

Sealing station A comprises a fusing burner 55, a dehydration orbreather hole making device 56, a forming, or shaping tool 57 and apolishing burner 58 all mounted on a frame support 59 extending into thefurnace 27.

The fusing burnet 55 comprises two rows of nozzles 60 mounted fordirecting flames onto the edge portions of the glass sheets as they arecarried past by the conveyor 29 and in that manner to raise theirtemperature sufficiently high to produce a pliable condition therein.

After the marginal edge portions of the glass sheets 21 and 22 have beenheated to a pliable condition by the flames from nozzles 66 the sheetsare moved into contact with the forming tool 57 comprising a pair ofhorizontally mounted forming wheels 61 which are driven by thefrictional engagement with the sheets. Preferably, see FIG. 5, each ofthese Wheels 61 has a lower cylindrical portion 62 of a uniformcircumference, while the upper portions are tapered to provide a concaveportion 63. As a pair of softened glass edges move through the formingtool 57 they are deflected from the surface of the concave portion 63inwardly to a point where the edges are fused together forming the edgewall 23.

While the edges of the glass sheets are being fused together by theforming tool 57, according to the invention the device 56 places .ahollow insert 64 between the marginal edges about to be fused and holdsthis insert in place until the glass edges are formed about itsufliciently to hold it in a tight sealed relationship. A more completediscussion of the structure of the insert 64 and the operation of theinsertion device 56 will be given below.

It was formerly common practice in the production of multiple sheetglazing units of the type disclosed herein to place dehydration orbreather holes in the face portion of the glass sheets before the edgeswere sealed. This type of breather hole was found to be unsatisfactoryin many instances because of breakage which occurred during drilling ofthe sheets or because of fissures emanating from the drilled holes whichproduced fractures when thermal shock took place. According to apreferred embodiment of the invention, to alleviate this condition thedehydration or breather holes 25 are formed in an edge wall 23 of aglazing unit as the edge wall is being formed. As given above, thedehydration hole according to the invention is produced by the insertionof a sleeve or insert 64 between the heated marginal edges of glasssheets 21 and 22 while they are being formed by the forming tool 57.When the glass edges have been formed around the insert 64, this hollowcavity produces the required access hole 25 to the space between thesheets.

A preferred form of insert 64 (FIG. 13) is that of a cylinder which whenpositioned in the sealed edge 23 of a glazing unit has its centralopening extending from the space between the sheets to the exterior ofthe glazing unit so as to be disposed with its long dimensionsubstantially parallel with the flat surfaces of the sheets andperpendicular to the sealed edge. By means of this access hole theinterior of the glazing unit may be dehydrated or charged with an inertgas after which the insert is sealed off preferably by placing a drop ofmolten solder into its exterior opening. A modified form of insert 65illustrated in FIG. 15 has a flanged portion 66 which, when the insertis properly placed in the edge wall 23 of glazing unit, is substantiallyflush with the outer edge wall surface. Of course there are any numberof possible shapes of inserts which may be used, however, the twodescribed above have been found to be the most satisfactory.

Although breather inserts may possibly be made from a number ofdifferent metals, alloys, or ceramic materials, the most satisfactoryresults were obtained with a cylindrical sleeve made from anickel-cobalt-iron alloy.

Referring now to FIGS. 4 through 8 there are illustrated the details ofa sealing station A incorporating the dehydration hole making device 56in accordance with the present invention. This device comprises broadlyan insert feed supply 67 .and an insertion device 68. The function ofthe former is to provide a continuous supply of inserts in position forbeing placed in the edge of a glazing unit while the function of thelatter is to insert the inserts in a properly timed relationship withthe fusing of the sheet edges.

The insert feed supply 67 comprises a body portion 69, a storage tube 76mounted on the body portion and in which a plurality of cylindricalgrommets are maintained in a fixed closely abutting relationshiptherein, and a reciprocating motion means 71. As can be seen best inFIGS. 6 and 7 the storage tube 70 is a hollow elongated structure soadapted as to be able to receive a plurality of cylindrical inserts 64-disposed in a line in the central cavity 72 with the openings of theinserts substantially at right angles to the long dimension of thestorage tube. A loaded spring 73 applies force to the line of insertsurging them away from the closed end of the storage tube and toward theopen or loading end 74. A pair of spring clips 75 secured to thevertical sides of the storage tube by rivets 76 (FIG. 9) engage and holdthe insert being forced outwardly of the open end 74 of the storage tubeby the spring 73. This action of the spring and clips provides acontinuous supply of these inserts in position for insertion. Thus, asshown in FIGS. 4 and 8 when this outer insert is pulled loose or removedthe force of spring 73 will move the next insert in the line from theend of the storage tube 70 into the grip of the spring clips 75 and inloading posi tion prior to insertion into the next glazing unit.

The storage tube 70 is fixedly secured to the body portion 69 which isso adapted as to be capable of being moved reciprocatingly toward andaway from the path of the moving glass sheets so that an insert 64 maybe placed on an insertion pin 77 and then the storage tube 70 and bodyportion 69 moved away to prevent interference with the glass sheets asthey move through the sealing station (see especially FIGS. 4, 6 and 7).The body portion 69 is provided with a longitudinally extending slot 78disposed .at a slight angle to the storage tube 70 so that when the slotis received by gudgeon 79 fixedly secured to support base 80 the bodyportion also moves slightly downwardly on being moved toward the path ofthe glass sheets and slightly upwardly on being moved away from the pathof the sheets. Adjacent the slot 78 there are provided a plurality ofspaced pins 81 extending outwardly from the surface of the body andarranged in a line parallel to the slot. A spur gear 82 is provided toengage the pin 81 so that the desired reciprocating motion of the bodyportion 69 may be produced on rotation of the gear. Thus, as is shown inFIG. 7 turning the gear 82 in a clockwise direction will provide first adownward motion of the storage tube 70 for placing the grommet beingheld by the spring clips onto the insertion pin 77. Further rotation ofthe gear 82 will cause it to engage the other pins to produce a movementof the storage tube and supporting body portion away from the path ofthe glass sheets and upward until the gear is engaging the rightmost pin(FIGS. 6 or 7) at which time the body portion and storage tube are atthe highest and farthest position away from the glass sheets. Furtherclockwise rotation of the gear 32 will move the storage tube and thebody portion toward the path of the sheets until the position is reachedwith a grommet being held again just above the insertion pin 77 asillustrated in FIG. 6 or 7. The grommet is loaded onto the insertionfinger 77 in .a timed relationship with the fusing operation and will bedescribed in that connecton hereinbelow.

The gear 82 is mounted on a shaft 83 suitably journaled in support 84with the other end of the shaft receiving a gear 85 driven by chain 86connected to driving gear 87 on the shaft of drive motor 88.

The grommet insertion device 68 comprises a body portion 89 mounted forreciprocating movement between a pair of sheets passing through thesealing station A and in a plane parallel to the sheets. This motion issuch that the insertion pin or finger 77 fixedly secured to the uppersurface of the body portion 89 is moved between the forming wheels 61and maintained in an upright position substantially parallel to theforming wheel drive shafts and then moved downward and away from theshaping tool 57. In its more specific aspects as illustratedparticularly in FIG. 5 the pin 77, after it has been loaded with aninsert 64, is moved toward the forming rolls 61 in the same direction asthe movement of the sheets and continues this movement until the pinreaches a point approximately on a line between the centers of theforming wheels 61. At this point the insert is also completely embeddedin and secured by the pliable edges of the glass sheets which have beenformed by the tool 57 and while still at this point a slight upwardmovement is provided to the pin in order to insure that the insert isfully seated in the edge wall 23. After this upward push the pinprojection 77 is then carried downward or away from. the sealed edgewall 23 leaving the insert sealed in place.

Examining the insertion device 68 in greater detail it will be notedthat the body portion 89 contains a longitudinal slot 90 for receiving apivot pin 91 mounted on side supporting walls 92 of the fusing burner 55substantially horizontally and transverse to the path of movement to thesheets. Adjacent the slot 90 on the body portion 89 there are provided aseries of pinlike projections 93 arranged in a substantially horizontalline and projecting outwardly from the body portion substantiallyparallel to the base support 94. At the end of the horizontal line ofprojections an additional projection 95 is placed lower than the otherprojections the purpose of which will be given later. A gear 96 ismounted so that it may engage the pin projections 93 and 95 and itsshaft 97 will extend beyond the gear hub to ride in a channel 98provided in the body portion 89 which completely surrounds theprojections. Rotating the gear 96, initially positioned as shown in FIG.6, in a counterclockwise direction moves the body portion 89 and theinsertion pin 77 carried thereby between the rollers 61. When the gear96 engages the lower pin 95 it provides the body portion and pin 77 withthe slight upward motion for sealing the grommet as described above. Asthe gear passes around pin 95 and begins to move along the upper part ofthe channel 98 the insertion pin is then dropped down to a lowerposition and further movement of the gear 96 moves insertion pin 77toward the fusing burners and away from the forming tool 57.

It is necessary that the insertion of an insert into a sealed edge of aglazing unit as described above be done in a timed relation with theloading of the insertion pin and with the sealing of the glass edges inorder to prevent mutual interference of these different operations.Thus, as an example, if the insert loading device 67 is left in itsloading position it will obstruct the passage of the glass sheetsbetween the forming rolls 61. Accordingly, to obviate interference ofthis sort a properly sequenced relationship of the various operationsinvolved is provided by an interlocking electrical network the diagramof which is given in FIG. 14. Assuming that an insert has been placed onthe insertion pin 77 and the conveyor 29 carrying a pair of glass sheetsto be sealed is moving along its path, the insertion operation isinitiated by cam 99 (FIG. 2) actuating switch 100 mounted adjacent theconveyor rails 40. Closing switch 100 provides a circuit from one sideof the power line 101, switch 100 (closed) points 102, wire 103, point104, wire 105, relay points 106 (closed), wire 107, and motor 108, theother side of the motor being connected directly to the other side ofthe powerline 109. Rotation of motor 108 turns cam 110 which closesswitch points 111 to provide a circuit from line 101, wire 112, switchpoints 111 (now closed), wire 113 and energizes relay 114 the other sideof which is connected directly to line 109. The energizing of relay 114closes relay points 115 to provide a circuit from line 101 through relaypoints 115 (now closed), wire 107 and motor 108 to keep it running.

As is shown in FIG. 7, motor 108 provides power through shaft 116, chain117, sprocket 118 (FIG. 8) mOunted on shaft 97 to turn gear 96 in acounterclockwise direction as viewed in FIG. 5 in order to move theinsert along the path described hereinabove and insert it between thesheet edges. Gear 96 is provided with an appropriate number of teeth sothat one revolution of the gear will cause it to completely traverse thechannel 98 which moves the insertion pin 77 from a position as shown inFIG. up between the forming wheels 61 then downwardly and toward thefusing burner and once again returned to the position in FIG. 5. Alsowhen motor 108 has made a complete revolution cam 110 restores points104 to a normally closed position and points 111 to a normally openposition. Opening of points 111 drops the circuit energizing relay 1114which opens up relay points 115 and the circuit to motor 108. Further,since the sheet carriage has passed farther along the path of movement,cam 99 has released switch 100 so that the motor 108 cannot be energizedas it was initially.

At this point the pair of glass sheets are partially fused and an inserthas been inserted in the edge wall. When the conveyor 29 has progressedto a point where the glass sheets are leaving the sealing station, cam119 (FIG. 2), actuates switch 120 which initiates the procedure forloading another insert onto insertion projection 77. At the beginning ofthe loading procedure the at rest position of the loading device is thatshown in FIG. 7 and is maintained throughout the sealing and insertionoperations.

Closing of switch 120 provides a circuit from line 101, switch 120(closed), wire 121, points 122 (closed), wire 123-, point 124, relaypoint 125 (closed) to one side of motor '88 with the other side of themotor connected directly to the opposite line 109. Energizing motor 88turns cam 126 which closes switch points 127 to provide a circuit fromline 1, points 127 (now closed) to ener-gize relay 128 the other side ofwhich is connected directly to line 109. Energizing relay 12 8 closesrelay points 129 to provide a holding circuit from line 101 to motor 88since the circuit through switch 120 is of short duration due to themomentary actuation of the switch by the cam 119.

Motor 88 will continue rotating until it has completed one revolution atwhich time cam 126 will return to the at rest position opening points127 deenergizing relay 128 which opens points 129 and drops the circuitto motor 88. As in the insertion procedure, one revolution of thedriving motor 88 provides a complete cycling of the grommet loading froma position as shown in FIG. 7 to loading an insert on insertion pin 77and returning the loading device 67 to a position as shown in FIG. 7. Atthis point the insertion pin is again loaded with an insert and isawaiting another pair of glass sheets for insertion as described above.

It is to be understood that the form of the invention herewith shown anddescribed is to be taken as a preferred embodiment of the same, but thatvarious changes in the shape, size and arrangement of parts may beresorted to without departing from the spirit of the invention or thescope of the subjoined claims.

I claim:

1. Apparatus for producing multiple sheet glazing units, comprisingmeans for supporting sheets of glass in spaced face-to-face relationwith respect to one another, heating means for raising the temperatureof the marginal edge portions of said sheets to substantially the fusionpoint of the glass, conveyor mean for effecting relative movementbetween said heating means and said glass sheets, forming means forurging the heated edge portions of said sheets into fusion contact withone another to form a sealed edge wall, and insertion means fordisposing a hollow insert in the edge wall of said unit, said insertionmeans including a body portion, a projection carried by said bodyportion for receiving an insert, a loading means for bringing saidinsert into operative engagement with said projection, and reciprocatorymoving means for moving said body portion so a to dispose said insertbetween the heated edge portions of said spaced sheets and then movesaid body portion away from the fused edge wall after the insert is insaid edge wall.

2. Apparatus for producing multiple sheet glazing units as defined inclaim 1, in which said loading means comprises a storage tube containinga plurality of inserts, means for urging the inserts through an openingin the tube, retaining fingers mounted on said storage tube adja-- centsaid opening for receiving an insert from said opening and holding it ina fixed position, and reciprocating motion means adapted to move saidstorage tube and retaining fingers into position for loading an inserton the projection of said insertion means and then away from saidinsertion means after loading.

3. Apparatus for producing multiple sheet glazing units as defined inclaim 1, in which sequencing means are provided for controlling thereciprocating movements of the loading means and the insertion means toobtain a predetermined sequence.

4. An apparatus for producing all-glass multiple sheet glazing units,which comprises means for supporting two sheets of glass in spacedface-to-face relation in a vertical position, heating means for raisingthe temperature of the edge portions of the glass sheets to the fusiontemperature of the glass, means for effecting relative movement betweenthe sheet supporting means and the heating means, means for positioninga hollow insert between the heated edge portions of said sheets duringforward movement thereof, and means for progressively urging the heatededge portions of the sheets during such movement into fusion contactwith one another to form a sealed edge wall and to simultaneously sealsaid hollow insert in said edge wall.

5. An apparatus for producing all-glass multiple sheet glazing units aclaimed in claim 4, including means for moving said insert positioningmeans and hollow insert with the glass sheets during sealing of saidinsert in the edge wall of the unit and for subsequently disengagingsaid positioning means from said insert and returning it to a positionto receive another insert.

6. An apparatus for producing all-glass multiple sheet glazing units asclaimed in claim 4, in which said insert positioning means includes avertical support element for receiving a hollow insert thereon and forholding the same substantially parallel between the heated edge portionsof the glass sheets during the fusing thereof to form a sealed edge walland in which means is provided for moving said support element with theglass sheets as the insert is being sealed into said edge wall.

7. An apparatus for producing all-glass multiple sheet glazing units asclaimed in claim 6, including means for removing the support elementaway from the fused edge wall after the hollow insert has been sealedtherein.

8. An apparatus for producing all-glass multiple sheet glazing units asclaimed in claim 6, in which loading means are provided for bringing ahollow insert into operative engagement with said support element, saidloading means comprising a storage tube containing a plurality of hollowinserts and having an opening at one end thereof, means for urging theinserts through the opening of the tube, retaining fingers carried atthe end of the tube adjacent said opening for receiving an insert fromsaid opening and holding it in fixed position, and means for moving thestorage tube and retaining fingers into position to load an insert onthe support element of the positioning means and away from saidpositioning means after loading.

9. An apparatus for producing all-glass multiple sheet glazing units asclaimed in claim 8, in which the insert positioning means and the insertloading means are connected in an electric circuit actuated by the sheetsupporting means for causing said positioning means and said loadingmeans to operate in timed relation to one another.

10. An apparatus for producing all-glass multiple sheet glazing units asclaimed in claim 9, in which said electrical circuit includes a switch,and in which actuating means is carried by the sheet supporting meansfor actuating the switch to cause the positioning means to position thehollow insert between the heated edge portions of the sheets.

11. An apparatus for producing a1l-glass multiple sheet glazing units asclaimed in claim '10, in which said electrical circuit includes a secondswitch, and in which a second actuating means is carried by the sheetsupporting means for actuating said second switch to cause the insertpositioning means to return to a position to receive another hollowinsert.

References Cited in the file of this patent UNITED STATES PATENTS1,448,351 Kirlin Mar. 13, 1923 2,688,824 Badger et al Sept. 14, 19542,761,249 Olson et a1 Sept. 4, 1956

